Hemlock Woolly Adelgid Treatment: What Are Woolly Adelgids

The tiny insects known as hemlock woolly adelgids have the ability to severely harm or even kill hemlock trees. Your tree is it in danger? Read this article to learn about treating and preventing hemlock woolly adelgid.

Woolly Adelgids: What Are They?

Woolly adelgids (Adelges tsugae), measuring only about 16 mm (2 mm) in length, are a major pest to hemlock trees in eastern North America. As a result of their feeding habits, the tree will starve to death if the infestation is not treated, turning its needles and branches brown and dying. Here are some fascinating details regarding these microscopic pests:

• There are female woolly adelgids only. They have asexual reproduction.
• They secrete waxy filaments during feeding, which eventually cover their bodies. Their “woolly” look comes from these filaments. The insects’ woolly coat shields them from predators as well as their eggs.
• During the summer, woolly adelgids hibernate, becoming active only when the weather cools down.

Damage from Hemlock Woolly Adelgid

The woolly adelgid is an insect that resembles aphids and can grow and reproduce on all kinds of hemlocks, with the exception of the eastern and Carolina hemlocks, which become infected and eventually die. Keep an eye out for any damage caused by hemlock woolly adelgid. Your tree has a much better chance of surviving if it is discovered early.

The insects consume the sap from hemlock needles, which eventually wither away one by one. The entire branch might perish if the infestation is not stopped. Below is a list of warning signs broken down by season:

• If you examine the base of the needles closely in the spring, you might notice orange-brown eggs.
• When the eggs hatch in the early summer, you might be able to spot tiny, crawling, reddish-brown insects.
• The best time of year to see insects is during the summer. They spin tiny white nests of a waxy, woolly material before going dormant in the summer heat. Compared to the insects themselves, the nests are much easier to spot.
• In the fall and winter, woolly adelgids emerge and start feeding once more.

Woolly Adelgid Management

Applying horticultural oils to a small tree is the most effective way to combat woolly adelgids. Follow the directions on the label and spray in the spring after the eggs hatch but before the insects start to crawl. Big trees won’t respond well to this technique. A systemic insecticide applied topically or by injection should be used to treat them. These are only temporary fixes.

Annual repetition of the treatment is required. Although there are no effective organic treatment techniques, researchers are collaborating with some of the woolly adelgid’s natural enemies to investigate potential uses for these enemies in hemlock tree protection.